Conventional coaxial cable connectors require that the connector be crimped to the cable to secure the connector to the cable. Such connectors suffer from two main disadvantages. First, crimping requires a crimping tool. This can be inconvenient because the tool may not be readily available, and in any event, such tools wear out with repeated use. Operators such as cable television installers typically require frequent replacement of their crimping tools. Second, crimping the connector around the cable does not provide a satisfactory seal. Crimped connectors typically permit leakage of radiation, and moisture penetration (which can interfere with signal transmission and which also exacerbates radiation leakage).
Certain crimpless connectors have recently been developed which attempt to overcome these problems.
One type of crimpless connector receives a plastic bushing, which is first broken away from a plastic ring mounted on the connector, and then slid over the cable and finally inserted into the annular cavity between the inner wall of the connector and the jacket of the cable. A special tool is required to push the bushing in fully. Two main problems exist with this crimpless connector. First, there is again a requirement for a special tool. Second, there is a tendency for the bushings to become lost before being put into use.
A second type of crimpless connector comprises a main body with a cylindrical mandrel having an inclined annular edge. A compressible ferrule is positioned within the cylindrical housing at the neck. The cable is inserted through the neck in the ferrule, with the cylindrical mandrel inserted between the foil and the jacket of the cable. When the connector is screwed onto a corresponding threaded coupling unit and tightened, the coupling unit bears on the end wall of the mandrel, pushing the annular edge towards the compressible ferrule. The ferrule then bears upon the jacket of the cable to provide a frictional engagement. One problem of this connector is that is has very little pull resistance until it is screwed onto a corresponding coupling unit and is thus prone to fall off the cable before it has been so connected. Second, it is difficult to know how tightly this type of connector must be screwed onto the corresponding coupling unit to provide satisfactory pull resistance.